The present invention relates to a technology which manages a configuration such as cache allocation, port bandwidth management and so on in a storage device.
As a mode which implements a new storage device in a computer system which has a server (host) and a storage device, there are an implementation mode which migrates all data in an old storage device to the new storage device and removes the old storage device, and an implementation mode which adds the new storage device with leaving over the old storage device and consolidates a storage area of the old storage device with the new storage device by a virtual volume.
As the former implementation mode, there is a data migration technology described in WO97/09676 (hereinafter, referred to as Patent Document 1). In this technology, a new storage device and an old storage device are connected, and a data migration process is carried out during operation of a system, and thereby, down time of the system for the data migration work is shortened. Concretely, a host computer and the new storage device are connected, and furthermore, the new storage device and the old storage device are connected. The new storage device copies data in an old storage device to its own storage area, The new storage device accepts an access request to data from the host computer even in a copy working state, and if the data exists in an own storage area, the data is accessed. In case that it does not exist in the own storage area, the data is firstly copied from the old storage device, and then, accessed. By such operation of the new storage device, it becomes possible to continuously operate the system even in a data migration working state.
Also, as the latter mode, there is a virtual volume technology described in United Kingdom Patent Laid-Open Publication No. 2351375 specification (hereinafter, referred to as Patent Document 2). In this technology, by a storage server having the following two functions, volumes assigned to a host are consolidated by virtual volumes. Function 1; a function which manages storage areas of each storage device which was connected to the storage server, and generates a volume pool. Function 2: a function which generates virtual volumes on the basis of one or more storage areas in the volume pool, and redirects I/O accesses to the virtual volumes from the host to corresponding storage areas, and responds to an I/O access from the host. Hereinafter, the storage server having such functions is referred to as a virtualization device.